Production of fast dyeings with ester-salts of leuco vat-dyestuffs



Patented July 4, 1933 UNITED STATES.

PATENT o1=1=1cE GEORGES DE mEnEnHAUsEEN, 0E BASEL, SWITZERLAND, ASSIGNOR TO THE Emu 0E nnmna H'U'GUENIN s.-A., 0F BASEL, SWITZERLAND PRODUCTION OF FAST D'YEINGS WITH ESTER-SALTS OF: LE'UCO VAT-DYFST'IJ'I?!S No Drawing. Application-filed April 19; 1929, Serial ifl'o. 356,621, and in Germany April 26, 1928.

Fromthe ester-salts of the leuco vat-dyestufi's (indigosols, seeU. S. patent specification No. 1,448,251) the original vat-dyestuffs can be re-formed through acid oxidation.

On this fact is based at dyeing process which has various forms of application and consists in principle in bringing such an ester-salt (indigosol) on to the fibre and then developing the dyeing on the latter by acid oxidation (re-formation of the dyestufl', see U. S. patent specification No. 1,575,958).

It has now been found that the development of ester-salts of leuco-vat-dyestufls compared with the hitherto known processes can be simplified and improved, since the surprising observation has been made, that the said estersalts (Indigosols) can be developed on the fibre under the action of water soluble cupric salts in the presence of an organic acid, being not injurious to the fibre, and other suitable ingredients, by means of a simple drying ope'ration. The drying process may be conducted at ordinary temperature or at a raised temperature; in the former case, the development of the dyeing proceeds more slowly than in the latter case.

'It isnot excluded that in the case of this oxidation with copper salts the oxygen of the air takes a part, the copper salts having probably also the function of a catalyst.

The indigosols may be brought on to the fibre by a printing or padding operation together with a cupric salt and also with an agent acting as an acid. Another method is to first impregnate the fibre with a cupric salt and subsequently to print the indigosol together with an acid. Through drying, advantageously at a temperature of 50-7 0 0., the dyeing is quickly and smoothly developed. The proportion of cupric salt to be used depends on the proportion of indigosol employed.

Certain auxiliary ingredients, such as for instance ethylenethioglycol, diethyleneglycolmonoethylether etc. promote or favor the operation of development.

The new process may be illustrated by the -following examples, the parts being by Weight: I

Example I A cotton piece is padded in a solution of:

P rt Copper sulphate crystals a s Tragacanth thickening 15 Formic acid 5 Vater 2 25 then wrung out and dried. The materialv thus prepared is then printed witha printing colour consisting of:

It is then dried, washed and soaped at the boil, whereby the dyeing is completely developed; in this way, bright, fast prints are obtained.

E wample II A cotton piece is padded in the following solution: t

. Parts Copper sulphate crystals Water 176 Tragacanth thickening. 10

Formic acid :,J 4

The material is then dried and printed with a printing colour consisting of:

. 1 Parts Ester-salt of tetrabromindigo V 5 Ethylenethioglycol 10 Tragacanth thickeningnu; 55 Lactic acid 2 Water 5 28 and thereupon dried at a temperature of about'7 0 C. Through this drying, the dyeing is smoothly and completely developed. 100

The material is finally washed and soaped at the boil.

' Example III The fibre is padded in a solution contain- Parts Ester-salt of 6 6-dichlor-7 7-dimethy1- thioindigo 6. G ethylenethioglycol 4 Water 15. 4 Starch and tragacauth thickening Then the whole is cooled down and when cold there is added thereto: Lactic acid 4 Copper sulphate, solution of 10 per cent strength 20 100 The material is thoroughly dried, preferably on drying cylinders. The completely developed prints are then washed and soaped at the boil.

In place of copper sulphate used in these examples, another cupric salt, such as for instance copper chloride, may be used to give the same results.

In this process ester-salts of all classes of vat-dyestuffs, such as those of the indigo, thioindigo, anthraquinone, quinone anilid series and so on can be employed.

lVhat I claim is 1. A process for producing fast dyeings with ester salts of leuco-vat-dyestuifs, which consists in applying on the fibre an ester salt of a leuco-vat-dyestufi' together with a cupric salt and an organic acid not injurious to the fibre, and performing the development by a simple drying operation.

2. A process for producing fast dyeings with ester salts of leuco-vat-dyestuifs, which consists in applying on the fibre an ester salt of a leuco-vat-dyestuif together with a cupric salt and an organic acid not injurious to the fibre, and performing the development by a simple drying operation at temperatures of 5070 C.

3. A process for producing fast dyeings with ester salts of leuco-vat-dyestuifs, which consists in applying on the fibre the ester salt of a leuco-vat-dyestuff together with cupric sulphate and an organic acid not injurious to the fiber, and performing the development by a simple drying operation.

4. A process for producing fast dyeings with ester salts of leuco-vat-dyestufis, which conslsts in applying on the fibre the ester salt of leuco-G: 6-diethoxythioindigo together with a cupric salt and an organic acid not injurious to the fibre, and performing the development by a simple drying operation.

In Witness whereof I have hereunto signed my name this 6th day of April 1929.

GEORGES DE NIEDERHAUSERN. 

